linux-stable.git/drivers/gpu/drm/drm_sysfs.c, branch v6.17

sysfs: treewide: switch back to attribute_group::bin_attrs

2025-06-17T08:44:15+00:00

The normal bin_attrs field can now handle const pointers.
This makes the _new variant unnecessary.
Switch all users back.

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-4-724bfcf05b99@weissschuh.net
Signed-off-by: Greg Kroah-Hartman

sysfs: treewide: switch back to bin_attribute::read()/write()

2025-06-17T08:44:13+00:00

The bin_attribute argument of bin_attribute::read() is now const.
This makes the _new() callbacks unnecessary. Switch all users back.

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-3-724bfcf05b99@weissschuh.net
Signed-off-by: Greg Kroah-Hartman

drm/sysfs: Constify 'struct bin_attribute'

2025-02-21T08:20:31+00:00

The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or malicious modifications.

Signed-off-by: Thomas Weißschuh 
Reviewed-by: Jani Nikula 
Reviewed-by: Andi Shyti 
Link: https://lore.kernel.org/r/20241216-sysfs-const-bin_attr-drm-v1-1-210f2b36b9bf@weissschuh.net
Signed-off-by: Greg Kroah-Hartman

drm/edid: add a helper for EDID sysfs property show

2024-05-23T11:37:24+00:00

Add a helper to get the EDID property for sysfs property show. This
hides all the edid_blob_ptr usage within drm_edid.c.

Reviewed-by: Chaitanya Kumar Borah 
Acked-by: Alex Deucher 
Link: https://patchwork.freedesktop.org/patch/msgid/902c8e09d25b99391fd9c92d95af07c01d7b7cbd.1715353572.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula

drm/sysfs: switch to drm device based logging

2024-04-15T13:22:05+00:00

Prefer drm_dbg_kms() and drm_dbg_lease() over DRM_DEBUG_KMS() and
DRM_DEBUG() to debug log the drm device info. Fix some debug categories
and unify connector logging while at it.

v2: Drop superfluous newline

Reviewed-by: Thomas Zimmermann 
Link: https://patchwork.freedesktop.org/patch/msgid/7f3dd5b4a33f964c6903c7a964da5397f4084aeb.1712568037.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula

drm/sysfs: Register "ddc" symlink later

2023-09-15T11:46:42+00:00

Currently drm_sysfs_connector_add() attempts to register
the "ddc" symlink (based one connector->ddc) before the
driver's .early_register() hook has been called. That is
too early for i915 which only fully registers the aux ch
and associated i2c bus from said hook (to prevent half
initialized stuff getting exposed to userspace). This
causes my attempt at using drm_connector_init_with_ddc()
to fail, and the entire connector disappears from sysfs
on account of sysfs_create_link() failing.

To fix that split the sysfs symlink stuff into separate
functions (drm_sysfs_connector_add_late() and
drm_sysfs_connector_remove_early()) which are called
on the opposite side of the .later_register() and
.early_unregister() hooks.

Cc: Andrzej Pietrasiewicz 
Cc: Daniel Vetter 
Cc: Andrzej Hajda 
Cc: Emil Velikov 
Cc: Sam Ravnborg 
Cc: Neil Armstrong 
Signed-off-by: Ville Syrjälä 
Link: https://patchwork.freedesktop.org/patch/msgid/20230829113920.13713-3-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula 
Acked-by: Thomas Zimmermann  #irc

drm/sysfs: rename drm_sysfs_connector_status_event()

2023-06-23T13:54:00+00:00

Rename drm_sysfs_connector_status_event() to
drm_sysfs_connector_property_event(). Indeed, "status" is a bit
vague: it can easily be confused with the connected/disconnected
status of the connector. This function has nothing to do with
connected/disconnected: it merely sends a notification that a
connector's property has changed (e.g. HDCP, privacy screen, etc).

Signed-off-by: Simon Ser 
Cc: Manasi Navare 
Cc: Sam Ravnborg 
Cc: Harry Wentland 
Cc: Daniel Vetter 
Reviewed-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20230620174231.260335-1-contact@emersion.fr

Merge drm/drm-next into drm-misc-next

2023-05-09T13:03:40+00:00

Start the 6.5 release cycle.

Signed-off-by: Maxime Ripard

drm/sysfs: Link DRM connectors to corresponding Type-C connectors

2023-04-28T20:21:14+00:00

Create a symlink pointing to USB Type-C connector for DRM connectors
when they are created. The link will be created only if the firmware is
able to describe the connection beween the two connectors.

Currently, even if a display uses a USB Type-C port, there is no way for
the userspace to find which port is used for which display. With the
symlink, display information would be accessible from Type-C connectors
and port information would be accessible from DRM connectors.

Associating the two subsystems, userspace would have potential to expose
and utilize more complex information. ChromeOS intend to use this
information for metrics collection. For example, we want to tell which
port is deriving which displays. Also, combined with USB PD information,
we can tell whether user is charging their device through display.
Chromium patch for parsing the symlink from the kernel is at
http://crrev.com/c/4317207.

We already have a framework in typec port-mapper.c where it goes through
component devices and runs the bind functions for those with matching
_PLD (physical location of device).
https://elixir.bootlin.com/linux/v5.18.1/source/drivers/usb/typec/
port-mapper.c
Since _PLD is ACPI specific field, this linking would only work on ACPI
x86 as long as _PLD field for Type-C connectors and DRM connectors are
correctly added to the firmware.

Currently, USB ports and USB4 ports are added as components to create a
symlink with Type C connector.
USB:
https://lore.kernel.org/all/20211223082349.45616-1-heikki.krogerus
@linux.intel.com/
USB4:
https://lore.kernel.org/all/20220418175932.1809770-3-wonchung@google.com/
So, we follow the same pattern in this patch.

Signed-off-by: Won Chung
Acked-by: Heikki Krogerus
Reviewed-by: Manasi Navare
Signed-off-by: Manasi Navare
Link: https://patchwork.freedesktop.org/patch/msgid/20230427165813.2844530-1-wonchung@google.com

drm/sysfs: Expose DRM connector id in each connector sysfs

2023-04-28T20:13:50+00:00

Expose DRM connector id in device sysfs so that we can map the connector
id to the connector syspath. Currently, even if we can derive the
connector id from modeset, we do not have a way to find the
corresponding connector's syspath.

This is helpful when determining the root connector of MST tree. When a
tree of multiple MST hub is connected to the system, modeset describes
the tree in the PATH blob. For example, consider the following scenario.

+-------------+
| Source      |    +-------------+
| (Device)    |    | BranchX     |
|             |    | (MST)       |
|       [conn6]--->|       [port1]--->DisplayA
+-------------+    |             |
                   |             |    +-------------+
                   |             |    | BranchY     |
                   |             |    | (MST)       |
                   |       [port2]--->|       [port1]----->DisplayB
                   +-------------+    |             |
                                      |       [port2]----->DisplayC
                                      +-------------+

DPMST connector of DisplayA would have "mst:6-1" PATH.
DPMST connector of DisplayB would have "mst:6-2-1" PATH.
DPMST connector of DisplayC would have "mst:6-2-2" PATH.

Given that connector id of 6 is the root of the MST connector tree, we
can utilize this patch to parse through DRM connectors sysfs and find
which connector syspath corresponds to the root connector (id == 6).

ChromeOS intend to use this information for metrics collection. For
example, we want to tell which port is deriving which displays even with
a MST hub. Chromium patch for parsing DRM connector id from the kernel
is at http://crrev.com/c/4317207.

Signed-off-by: Won Chung 
Reviewed-by: Manasi Navare 
Signed-off-by: Manasi Navare 
Link: https://patchwork.freedesktop.org/patch/msgid/20230329014455.1990104-1-wonchung@google.com